Modified cellulose and similar polysaccharides are known to have a variety of uses in the form of powders and solutions. Applications are known in foods, pharmaceuticals, oil drilling, etc. Still in spite of all known uses and applications, it remained for the present invention to advance the State-of the-Art for invert emulsions.
Bentonite clay is commonly used to retain water within diaphragm walls during construction. A disadvantage of this material is that the clay must be disposed of after it has served its purpose.
Ullmans Encyclopadie der technischen Chemie, 4th Edition, Vol. 9, pp.192,209, refers to the use of water soluble cellulose ethers such as sodium carboxymethylcellulose for use for diaphragm wall construction. Modified cellulose ethers and their use as thickeners and dispersion agents are described in U.S. Pat. Nos. 4,228,277, 4,336,146, 4,720,303 and 4,799,962. But in spite of what was previously published and known to workers in the construction field, prior attempts to use cellulosic polymers for diaphragm wall construction were not completely satisfactory due to the inability to prevent water loss from the filled trench into the surrounding soil. As a result, clay continued to be used for diaphragm wall construction in spite of the environmental advantages of the use of a biodegradable polymer such as cellulose.